Novel robot platform for stripping and/or painting and resulting work stations

ABSTRACT

A technical system comprising a structure within an enclosed space, inside which paint-stripping and refurbishing operations for aircraft, rail rolling stock or sea-going vessels are carried out, comprising:  
     an accommodation workshop for the craft to be stripped,  
     at least one appliance for stripping or painting,  
     a storage site for paints ( 1 ),  
     at least one site for personnel ( 2 ),  
     an office for supervision of the stripping and medium-reprocessing operations ( 3 ),  
     a site for compression devices ( 6 ),  
     a site for reprocessing ( 4 ′) and storage ( 4 ) of the abrasive material,  
     a cabin for stripping components after dismantling ( 5 ), connection blocks ( 8 ) installed permanently to supply power to the nozzles for dry-blasting with a medium, fed by compressed air, mobile or fixed stripping stations ( 12 ) surrounding the craft to be stripped, pipes distributing the abrasive agent ( 9 ) and an abrasive medium which attacks the paintwork without damaging the primer coating.

[0001] The present invention relates to the layout of new technical apparatus and to the arrangement of new workshops thus created.

[0002] The invention concerns more particularly the equipping of an enclosed site in which maintenance operations, and paint-stripping and paint application operations are carried out.

[0003] The invention concerns specifically the layout of a site and in particular a hangar which makes possible paint stripping and paint application operations for land vehicles, sea-going craft and aircraft, by means of a stripping agent involving a dry blasting process using one or more blasting nozzles arranged at one or more paint stripping stations which are remote controlled.

[0004] The invention concerns in particular an installation designed to control stripping and/or painting operations by blasting a stripping agent intended for stripping airframes, by means of nozzles arranged around all the periphery of the immobilized vehicle inside the installation, as well as the stripping and or painting stations and the equipment used.

[0005] The minimum load of this installation may be 16 aircraft initially, but this can be increased to 50 aircraft which are stripped over 313 working days.

[0006] The stripping operations can be carried out manually by operatives or by remote-controlled appliances determining the conditions and the parameters of the stripping or painting procedures.

[0007] Transport companies, and especially airlines, taking into account their projected work schedules for the next ten years and the cost of a bulk transport aircraft, must be able to keep the same craft in good flying condition for at least twenty and even thirty years. It has therefore become necessary, when carrying out maintenance operations and general overhaul to make sure that the paintwork on parts most exposed to corrosion is in good condition and that the materials protected by this paintwork are free from any damage. This necessitates maintenance operations and it is desirable that these should be carried out at as low a cost as possible, with minimum craft immobilization.

[0008] This is just as true for railway rolling stock. It is well known that the front parts of high speed train engines suffer from the effects of being blasted by dust and corrosive agents and the paintwork can undergo widespread damage, and indeed even be partly stripped away. The same is true for ships which have to be placed in dry dock to strip down the metallic or plastic sheet-panels and remove the living organisms which become encrusted on the ship's hulls in the space of a few months.

[0009] However, the problem of paint stripping is not a simple problem as, if the method of sand blasting under pressure is used, the materials protected by the paint are rapidly torn during the stripping operations, whereas, during stripping operations, the parts stripped should not be damaged.

[0010] Under these conditions, stripping is going too far and can even damage or scratch the sheeting. On the other hand, if the abrasive agent is not hard enough, it will be able to remove flakes of paint or dust but will not enable exposure of the coating layer. Furthermore, during the stripping operation, fragile parts or those not needing stripping (parts made from rubber, plastic or aluminium material) should not be subjected to corrosive action.

[0011] Bearing in mind the constraints outlined above, it was important to be able to have a suitable area and to determine the different parameters of the stripping process.

[0012] In a method for creating the layout of the stripping units according to the invention, it is proposed that the stripping operation is effected by blasting with a dry medium by means of an optimized blasting nozzle, handled by an operative, and supplied with a medium/compressed air mixture by means of a generator.

[0013] The air/medium mixture delivered to the operative's nozzle is created by a generator made up of a pressurized canister containing a certain quantity of abrasive at utilization pressure and a specific remote-controlled distributor, allowing the desired quantity of medium to pass into the flow of compressed air. The flexible pipe conveys the mixture between this generator and the nozzle, with the minimum of losses and of wear and tear.

[0014] To precisely control the blasting conditions, each blasting nozzle has its own generator, distributor, and supply pipe.

[0015] Thus the blasting conditions can be adjusted for each nozzle depending on the nature of the material to be stripped. These stripping conditions are imposed by the supervisor.

[0016] The stripping is carried out by blasting using an optimized compressed-air blasting nozzle, handled by an operative provided with protective equipment.

[0017] Depending on the coatings or the substrates to be treated, the air pressure for blasting can vary from 1.5 to 3.5 bar with a flow rate of 200 to 350 Nm³/h, and a medium flow rate from 1 to 3 kg/min. The pipe delivering the mixture of abrasive air has an external diameter of approx. 50 mm.

[0018] To provide a cycle time compatible with the constraints of the maximum time for immobilization of the craft, it is necessary to provide 5 to 7 simultaneous work stations, according to one study (comparative dimensionnement process [sic]).

[0019] The zones to be treated are not always, or most of the time, accessible at the right height for a man. Their treatment thus necessitates the use of transport carriages or cradles arranged around the craft. These carriages or cradles are mobile, and can if necessary be moved during the stripping phase.

[0020] The medium is blasted on to the zones to be stripped, and a mixture of reusable medium, used medium and paint and/or stripped off waste falls mainly to the floor of the workshop. Retention zones are thus necessary.

[0021] The blasting system used is based on the traditional operation of pressure-type compressed air blasting machines.

[0022] The air/abrasive mixture, delivered to the operative's nozzle, is created by a generator comprising a pressurized canister containing a certain quantity of abrasive at utilization pressure and a distributor allowing the desired quantity of medium to pass into the flow of compressed air. The flexible pipe conveys the mixture between this generator and the nozzle, with the minimum of losses and of wear and tear

[0023] It is preferable that each blasting nozzle should possess its own generator and feed pipe.

[0024] The abrasive mixture falling to the ground must be recovered for subsequent reprocessing. Technical-economic optimization of the process necessitates recovery of the medium and separation of the reusable part of the mixture from the waste. Taking into account the specific granular size of the medium, the rate of recovery is about 80%. The medium recovered and the new medium are used to supply the generators.

[0025] In conclusion, the preceding analyses lead to the observation of some determining points in the layout of the technical system according to the invention,

[0026] If the generators feeding the nozzles are installed permanently, they are necessarily situated at a certain distance from the craft to be treated, the closest being along the partition walls of the workshop. This involves the presence of so many supply pipes for the nozzles on the workshop floor. Apart from the losses of charge and the wear and tear linked with minimal lengths, the nuisance caused by these pipes is considerable: their being heavy to use (tidying away, cleaning and storage), being a hindrance to traffic, difficult for the operatives to handle (weight, time of response, etc . . . )

[0027] It is not necessary to have generators with very large quantities of medium. Approximately 50 liters are sufficient to allow continuous blasting, without interruption, for 20 minutes, a few minutes then being enough to recharge the pressurized canister from an intermediate tank.

[0028] Recovery of the medium blasted and of the waste is a not inconsiderable operation, and taking this into consideration should make it possible to achieve more efficient and more productive use than that which exists today. It should be carried out as rapidly and completely as possible, both to minimize the time cycle and to guarantee repainting of the craft in the best possible conditions.

[0029] The stripping medium or agent used in the stripping appliance according to the invention is one of those described in the French patent 2,761,365 under the name of the Joint-Trade Organization Biodecap. In particular, for this purpose a vegetable polymer derived from wheat flour, reticulated by a chemical agent is used, which has abrasive properties notably enabling the stripping of aeronautical paintwork systems, while preserving the substrate from any damage. The painting system used for planes, train engines or boats consists of a system formed from a coat of primer and different functional coats (anti-erosion, anti-corrosion). The primer coat is intended to provide cohesion between the substrate and the functional coats.

[0030] Specifically, the layout of the technical system according to the invention is in particular formed by a mobile stripping unit, monitored and activated by remote control and comprising:

[0031] an accommodation workshop for the craft to be stripped,

[0032] one or more appliances for distributing the stripping material,

[0033] one or more sites for storage, equipment, processing and storage of the stripping material,

[0034] a stripping cabin for dismantled components,

[0035] an office for supervision of the stripping operations and reprocessing of the stripping material,

[0036] All these sites are interconnected by means of computer or power links.

[0037] A method of creating the layout according to the invention is shown in FIG. 1, this shows the structure of a hangar (11), inside which an aircraft is represented during stripping and reconditioning operations. The layout comprises successively:

[0038] 1. a site for storing paint (1)

[0039] 2. sites or the personnel (2)

[0040] 3. an office for supervision of the stripping and medium-reprocessing operations (3)

[0041] 4. a site for tidying away equipment (7)

[0042] 5. a site for the compressors (6)

[0043] 6. a site for reprocessing (4′) and storage (4) of the abrasive material

[0044] 7. a cabin for stripping components after they have been dismantled (5)

[0045] On the apron there are, in addition:

[0046] 1. power supply connection blocks (8)

[0047] 2. mobile stripping stations surrounding the craft to be stripped (12)

[0048] 3. pipes distributing the abrasive agent (9)

[0049] The following will also be noted: an inlet for paints (A), an outlet (B) for paint wastes, an inlet for new medium (C), an outlet for the medium wastes (D), an outflow for new or reprocessed medium (E) prior to being directed towards stripping and an inlet for the medium after blasting (F).

[0050] The lines (10) represent the computer and power links between the junction boxes and the stripping points. These are flexible links connecting a fixed block and a mobile station whose position is determined by the shape and size of the craft to be reprocessed.

[0051] After stripping the craft, the medium will be recovered by suction and the other waste will be removed from it by a filtering system. Particular attention will be given to maintaining a sufficient grain-size to allow recycling of the abrasive material. The generators (8) supplying the nozzles (12) are installed permanently, being situated at a certain distance from the craft to be processed, the closest being placed along the partition walls of the workshop. This involves the presence of a number of supply lines to the nozzles equal to that of the generators on the hangar floor. Care is taken that the charge losses, wear and tear connected with the length of the pipes and the nuisance caused by the presence of these pipes, such their being heavy to use, and causing hindrance to traffic and difficulty of handling for the operatives, can be kept to a minimum, but unless special precautions are taken they can become quite considerable.

[0052] The soiled medium falling on the ground is recovered and then recycled. By means of filtering, it is possible to recover up to 80% of the medium used. The medium recovered is mixed with new medium so that it can be used in a new operation.

[0053] The stock of medium does not have to be large, approximately 50 liters being sufficient to permit continuous blasting without interruption for 20 minutes. It is then necessary to re-supply the compressor's pressurized canister from a supplies store. A few minutes suffice for this operation.

[0054] In the layout according to the invention each blasting nozzle has its own generating unit mounted on an independent trolley, This trolley, shown in FIG. 2, can be easily moved on the ground and is adjustable in height. It can thus be placed in the best possible position for the zones to be treated and the dimensions of the craft to be stripped.

[0055] This positioning of the generating equipment makes it possible to appreciably reduce the length of the pipes delivering the abrasive and consequently:

[0056] charge losses are limited

[0057] lengths of pipe on the ground are shorter, which facilitates the recovery of medium which has fallen onto the ground

[0058] the risk of collision between the airframe and the pipes is reduced

[0059] the ergonomic arrangement of the operatives' stations is improved

[0060] On the other hand, the delivery of the power sources to the trolley (23) has to be adapted to requirements. For this purpose, during construction, the workshop is equipped with buried technical channels or conduits, enabling the passage of necessary flows (compressed air, electricity, etc.) between technical sites (compressors, electrical cabinets) and connection hatches arranged judiciously around the craft to be treated.

[0061] The stripping trolley (23) is shown in FIG. 2. This can be moved by an operative and comprises:

[0062] 1. a generator or pressurized canister (17) with a capacity of about 50 liters. The supply pressure from this generator is also monitored by the supervisor.

[0063] 1. a distributing unit (18) which allows remote control of the medium flow rote notably by means of a jack (22)

[0064] 2 valves (15) and (15′) effecting the medium's isolation from and supply to the generator (17) from an intermediate open-air hopper (14) situated over the trolley (23)

[0065] 3. a flexible-bag (big bag) supply support (13) holding approximately 500 liters placed above the hopper (14).

[0066] 4. an electro-pneumatic automaton which makes possible local treatment of the stripping unit operation, the operation of this unit itself being dependent on the supervisor's instructions:

[0067] start up or shutdown of blasting

[0068] automatic recharging depending on the medium available in the hopper 14

[0069] regulation of the flow rate and pressure

[0070] exchange of data with the supervisor and receipt of instructions from the supervisor

[0071] sending of information to the supervisor about any incident which may occur during the stripping operations

[0072] audio link with the supervisory office

[0073] safety appliances

[0074] appropriate storage for different pipes and cables (19).

[0075] Thus, everything can be assembled after use and replaced on the base of the mobile trolley (23), which is moved by means of two large wheels forming an integral part of the framework and two scaled-down wheels which can move on a horizontal plane (25).

[0076]FIG. 2 shows the mobile trolley (23) in elevation (FIG. 2A) or from above (2B).

[0077] On this figure, the trolley can be moved by a human operative. It is clear that movements could be remote controlled and/or effected by an electric motor.

[0078]FIG. 2A shows a weighing system (16) of the generator (17) viewed in profile (the same weighing system (28, 28′, 28″) seen from above is shown in FIG. 2B). A device for distributing the abrasive (18) is situated at the base and is remote-controlled by means of a mechanical or pneumatic shut-off device (22). These elements (weighing and shut-off device) enable the supervisor, by means of the automaton, to control the flow rate of the medium, whatever its grain size.

[0079] At (20) a dummy is shown, moving the trolley (23) by means of two handles (30), carrying out on request the necessary horizontal, vertical or lateral movements necessary for adjusting the position of the station in relation to the craft to be stripped.

[0080]FIG. 2B shows the trolley (23) seen from above, on which the electrical control cabinet (26), and the access points for maintenance (24) (24′) are shown.

[0081] In practice, the supply support in the flexible receptacle (13) has a capacity of approximately 500 liters. This volume can easily be modified from 200 to 2000 liters.

[0082] The medium supply support in the flexible receptacle (13) has a capacity adapted to needs.

[0083] The layout according to the invention thus comprises an accommodation hangar for craft whose dimensions may vary from 50 to 150 m in length and 10 to 25 m in width.

[0084] The mobile trolleys used for blasting the medium are 1,500 to 2,000 cm in length, with a height above the ground of between 300 and 500 cm, a flexible receptacle, cylindrical-conical in shape, of 900 to 1,200 cm in height for a diameter of 800 to 1,000 cm. The height of the gantry supporting the distribution system varies from 1,100 to 1,500 cm. The total height of the mobile trolley varies from 2,500 to 3,000 cm. The overall width of the trolley ranges from 1,800 to 2,200 cm.

[0085] The abrasive flow rate is between 0.5 and 6 kg/min at a pressure of between 1 and 6 bar. 

1. Layout of a technical system comprising a structure within an enclosed space, inside which paint-stripping and re-furbishing operations for aircraft, rail rolling stock or sea-going vessels are carried out, comprising: an accommodation workshop for the craft to be stripped one or more appliances for stripping or painting, a storage site for paints (1), one or more sites for personnel (2), an office for supervision of the stripping and medium-reprocessing operations (3), a site for the compression devices (6), a site for re-processing (4′) and storage (4) of the abrasive material, a cabin for stripping components after dismantling (5), characterized in that the layout utilizes, in addition, connection blocks (8) installed permanently and serving to supply power to the nozzles for dry-blasting with a medium, fed by compressed air, mobile or fixed stripping stations (12) surrounding the craft to be stripped, pipes distributing the abrasive agent (9) and an abrasive medium which attacks the paintwork without damaging the primer coating.
 1. Layout according to claim 1, characterized in that it also includes an inlet for paints (A), an outlet for paint wastes (B), an inlet for the new medium (C), an outlet for the medium wastes (D), an outflow for the new or reprocessed medium (F), and an inlet for the medium after blasting (E), the abrasive medium being formed from wheat flour that has been reticulated and calcined.
 1. Layout according to claim 1 or claim 2, characterized in that the connection blocks (8) are linked to the stripping stations (12) by computer and power connections.
 1. Layout according to claims 1 to 3, characterized in that the medium is recovered by suction and other wastes are removed from it by a filtering system.
 1. Layout according to claims 1 to 4, characterized in that the nozzles for dry-blasting with a medium are moved manually by operatives.
 1. Layout according to any one of claims 1 to 5, characterized in that the soiled medium falling onto the ground is recovered and then recycled.
 1. Layout according to any one of claims 1 to 6, characterized in that the medium recovered is mixed with the new medium so that it can be used in a new operation.
 1. Layout according to claim 5, characterized in that each blasting nozzle (12) has its own generating unit (8) mounted oil an independent trolley that can be moved about on the ground and is adjustable in height.
 9. Layout according to claim 8, characterized in that the stripping trolley (23) comprises a pressurized canister, a distribution unit allowing regulation of the medium flow rate, valves effecting the isolation of or supply from the generator and a flexible bag-type supply support placed above a feed hopper.
 10. Layout according to any one of claims 1 to 9, characterized in that it comprises an automatic or semi-automatic control device which makes possible local treatment of the unit's operation.
 11. Layout according to any one of claims 1 to 10, characterized in that the flow rate of the abrasive is between 0.5 and 6 kg/min, whilst operating at a relative pressure of between 1 and 6 bar.
 12. Layout according to any one of claims 1 to 11, characterized in that the recycling or supply apparatus has a capacity varying from 200 to 2,000 liters and preferably of the order of 500 liters.
 13. Layout according to any one of claims 1 to 12, characterized in that it comprises means designed to effect the stripping and reconditioning of aircraft, sea-going craft and land vehicles, and in particular planes, boats or trains. 